His Second Heart
by 4everafter
Summary: Set after The Siege of Big Ben. The Doctor reflects on the events of the day, before finally having a chance to talk to Rose about it all. One-shot. Some angst, and plenty of fluff.


**Of course, I don't own Doctor Who. Please enjoy!**

* * *

The Doctor paced his lab. Only a couple of hours earlier, he had thought that this room, with its books, test tubes, and monitors lining the walls, and its gadgets spread out haphazardly on the three work tables, would be the last place he'd ever see. This room that housed the pulsing, growing (well, it _had_ been growing but wasn't growing right now) baby TARDIS that had caused so much trouble today.

When the UNIT alerts had sounded throughout HQ, located in Big Ben – yes, the actual clock tower in London – the Doctor had to admit he had been a little excited. It had been a quiet week until the phone call about the rediscovered Cybus factory in Bridlington. The entire team was sent out there, and he had been set to go as well, but then one of his experiments had gone a bit haywire, and Rose had told him she could handle the factory with the rest of the team, and he had better make sure he didn't accidentally blow up Big Ben.

Wasn't that ironic?

So when the alarms had sounded, he, having finished containing his rouge experiment and a little put out at missing an adventure, had really only had one worry. Not who was invading or why, but that the only other person in the building was Jackie Tyler. Now, Rose's mum could handle herself, though she didn't really have much self-confidence, but she was just one person and Rose would never forgive him if he let her mum get taken by aliens, and he wouldn't really forgive himself, either, so he had rushed down to the kitchens to find her.

Jackie had been unharmed, and he put on his usual show of being confident and unaffected – that always seemed to calm panicky humans down. But then before he knew it she had practically bullied her way into his lab and they were talking to one of the aliens they could see on his monitors and she was shouting at it and him. Honestly, he had only been trying to make sure she was safe!

Somehow the alien had known about the TARDIS. And then they said the words that nearly made his newly single human heart stop. _"We have Rose Tyler."_ They'd said they had Pete, too, and others from UNIT, but Rose… he couldn't lose her. Not now, not after just getting her back.

But aliens with nefarious intentions - because if they were threatening a zeppelin with Rose on board to get themselves a time machine, then they were definitely not pure and innocent beings - could not get their hands on a TARDIS, operational or not. So, he went with the first solution to pop into his head that seemed like it had a decent chance if success.

Telling Jackie he was going to blow up Big Ben had not gone over well. In the end though, he hadn't needed to, because something Jackie said had made him think – how did they know about the TARDIS? Very few did – him, Rose, Jake, and...

He really should have seen it. But Brigadier Krista Latif had been a friend to him since he'd arrived in this universe, and one of the few who knew who and what he was. She had approved his hiring, and this lab situated at the top of Big Ben. And then she was holding a gun on him and Jackie and demanding he go back and change time so her daughter would survive the Cybermen attack he and Rose had stopped when they had first visited this universe. There was no alien invasion, no captured zeppelin holding Rose Tyler, just a desperate woman with the means to stage everything to get what she wanted.

In the end, Jackie had saved the day. She had talked Krista out of shooting them. All he'd had to do was say four words, a lie just like hers – _"I won't tell anyone."_

When he'd turned around and done exactly the opposite, he could feel Jackie's disappointed stare. But he'd made up his mind. Even now, after having been reunited with Rose (who hadn't mentioned how he'd hugged her just a little tighter and kissed her a little longer), and leaving her to talk to her mother who insisted on a word with her "in private", he couldn't bring himself to regret his decision.

He heard the door to his lab open and shut quietly. He knew who it was before he spun around to face them - Rose Tyler was the only other person with a key. Supposedly because she was his assistant, even though she also held the title of Extraterrestrial Relations Specialist, although the two jobs did overlap quite a bit, but really because she was his partner in, well, everything, now. He didn't keep secrets from her anymore.

He watched Rose sigh and lean back against the door.

"Jackie's angry with me." It was a statement because he really didn't have to ask.

Rose nodded. She didn't keep secrets anymore, either. "Yeah." Her eyes held sympathy, and he was relieved she didn't seem to be angry with him, too.

He felt compelled to defend himself anyway. "I know she wanted me to give Krista another chance, Rose, to not tell anyone what she did, but I just, I couldn't," he finished quietly, shaking his head.

She gave him a small smile. "Well, I hope you would have still told me."

"Of course." His reply was automatic.

She tilted her head as she regarded him. "But why didn't you, Doctor? Why didn't you let her go?" The question held no bite, but he still flinched.

"She threatened to kill you, Rose." He'd meant to sound firm, but his words came out strangled. He took a breath, then continued. "I mean, obviously it wasn't real, but at the time…" he trailed off.

"Doctor," Rose said softly, coming closer to take his hand.

He looked down at her. "I was scared. Of course I tried to keep up a strong front for your mum, but Rose, I thought I might lose you. And we've barely," he nearly choked on a lump on his throat and had to pause, "we've only just found each other again."

She hugged him at that, and he found himself breathing a little easier. "I know she had an attack of conscience this time, but I also know that kind of grief can drive you mad," he told her, "so what happens next time she lets it take over? She faked it all this time, but that didn't work. Next time," he pulled back to look at her, and he knew his fear was evident in his eyes, "next time would she actually try to take you from me? To hurt you, or…or worse." Rose reached up to stroke her fingers through his hair comfortingly, and he sighed. "I couldn't take that chance."

"I get it," Rose said, giving him a sad smile. "I hate that it ended like this, but for what it's worth, I think you made the right call. The position Krista has, had" she corrected herself, "well, she could do a lot of damage."

He shook his head, inexplicably wanting to disagree with her when she had just said he was right. He could still hear Jackie's words from earlier, rattling on about how he used to be. Would he have shown Krista more mercy, if he had still been, well, _him_?

 _"No second chances."_

 _"Don't you think she looks tired?"_

 _"You get one warning. That was it."_

Hmm… perhaps not. He blinked a few times, coming back to the present before the memories went any further. "I once promised never to be cruel," he whispered.

Rose furrowed her brow at him. "You aren't." She took his hand in hers, squeezing it. "And you weren't. You made the best decision you could to protect everyone. Including Krista herself."

He scrubbed a hand down his face, but then nodded. "It's just harder now, sometimes," he said, looking away from her but not letting go of her hand, "sticking around to deal with the consequences. There are no do-overs."

She nodded, drawing his eyes back toward her, and her grip on his hand loosened. "Yeah, speaking of…" And oh, she _was_ angry. He saw a scary little flash in her eyes as she paused and glared at him. "Maybe that's why I wasn't thrilled to hear that your original plan was to blow up Big Ben?!" The last bit came out as a shout. "With you inside! Not to mention my mum. What were you thinking?!"

"I would've gotten Jackie out, Rose," he told her.

"And you?"

Her eyes bored into his and he found it difficult to hold her gaze. "I… would have needed to make sure the TARDIS was completely destroyed." She shook her head and pulled completely away from him, crossing toward the baby time ship. "She can't fall into the wrong hands, Rose!"

She didn't answer for a beat, leaning towards the little TARDIS and reaching out to softly stroke her before replying, "Could you really have done it?" She looked back at him. "Destroyed her?"

He considered her for a moment before shrugging. "I love you," he said simply. He really had no better answer. There was really nothing he wouldn't do for Rose Tyler. And maybe that was actually made him more dangerous than the Time Lord him. The human emotion that could so easily quash his willpower. Had this been the version of him who had first lost her to Pete's World, he very well may have chosen her over the safety of two universes.

Her eyes softened and she gave him a small but genuine smile. "I love you, too, Doctor." She turned fully towards him again but didn't approach him, shoving her hands in her pockets. "But that's why this scares me. You're go-to plan was to sacrifice yourself and the TARDIS. But I couldn't..." She took a shuddering breath and he could tell she was blinking back tears and oh he absolutely hated it when she cried. He took a step in her direction. "I don't think I could take losing you, not again."

"Oh, Rose Tyler," he breathed, and he covered the rest of the distance between them in a second and gathered her up in his arms again; now it was him giving the comforting hug. "You're one of the strongest people I know. You could get through anything, with or without me."

"I'd rather it be with you," she murmured. "Doctor, he gave us a gift," and he didn't have to ask who he was, "and I want to enjoy this life together for a very long time." She pulled back just enough to place a hand on his chest, over his heart. "You've got just one of these now," she said, looking up at him. "I love what we do, defending the earth, and someday we'll be out there saving other worlds, too, and I wouldn't trade it even with all the danger. But Doctor, I don't want my mum or anyone else to have to tell you to find another way. That should be your first instinct. I've always done my best to come back to you. _I need you to do the same_."

And that's when it clicked. That's when he understood. She loved him like he loved her. He still couldn't really fathom why she loved him, but she did, and that meant that she wanted him safe, just like he wanted her safe.

He brought a hand up to cradle her head, and leaned down to kiss her. He tried to pour as much love and reassurance into the kiss as he could, thinking how much easier that would be if they had a bond. (A bond with Rose might also have been useful earlier – being able to talk over a distance would have clued him in that the captured zeppelin was a lie.) They had connected telepathically a couple of times since he'd been here, but he still hadn't worked up the courage to ask her for anything more, unsure how she'd take the idea of the constant, permanent nature of that kind of link. He wanted to marry her, in the way of her people _and_ his, but he was always a coward. It seemed, however, that he was running out of reasons to be afraid of being closer to Rose.

Right now, though, he had a promise to make. He eased out of the kiss and framed her face with his hands. "I'm so sorry, Rose," he said. "I didn't realize… I'm not used to having to be careful…"

"I'm not asking you to stop being you, Doctor," she cut him off before he could continue. "I said, I love what we do…"

"I know," he interrupted. "I know, Rose. Please just let me finish." She nodded. "I'm not used to having to be careful because I'm not used to having someone to come home to. But, love, I promise to do better. And I promise, Rose," he slowed his words, making sure she understood he meant this, "I will always do everything in my power to come home to you."

This time the tears he saw in her eyes were happy ones, and he saw her smile at him briefly before she was kissing him again. "Thank you, Doctor," she whispered as she pulled back.

"Anything for you, Rose Tyler," he replied, and he wondered if she knew how much he meant it. Jackie's words were still echoing in his head. _"You need to be better!"_ That's why he needed Rose – she didn't just make him better, she made him _want_ to be better for _her_.

"Come on," she said , pulling him from his thoughts, "let's get out of here. I don't know about you, but I could go for Chinese."

He grinned, taking her abrupt change of topic easily. "Sounds brilliant."

She paused again by the TARDIS. "Good night, dear," she told the baby ship.

He smirked at her talking to the ship – she used to tease him for doing the very same thing once upon a time – but then grimaced, suddenly remembering, "You're mum wasn't thrilled to discover her."

Rose gave him a wry smile. "I told you not to tell her about it 'til she was all grown." The Doctor never gave Jackie a straight answer when she had asked what he would really do with the chunk of coral the full Time Lord had given him straight after the incident, as he hadn't discussed it with Rose yet, and they knew she'd eventually assumed he wouldn't pursue it. When they did decide to try and grow the TARDIS, Rose had thought it best not to make her mum start worrying about it too early by bringing it up.

"I didn't have a choice!" he exclaimed. "I tried to keep her outside but she insisted on coming in here!"

"Sounds like mum," Rose replied, chuckling.

"She accused me of planning to leave you, sneak off without you," he said, and he tried to keep the hurt out of his voice, but by the way Rose looked at him, he didn't think he completely succeeded.

"She actually said that?"

He sort of regretted bringing it up now. "She also said that if I was planning on bringing you, that I would have to bring all the Tylers, and we all know how _that_ would go." He infused as much dramatic exasperation as he could into his tone, and threw her a big grin, which she automatically answered. Then, as casually as he could manage, he turned away, ostensibly to gather his things.

"Doctor." Her voice was sympathetic, but chiding. She wasn't fooled by his deflection. How did she know him so well?

"It's just," he spun back around to face her, "how could she not know?" Another thought occurred to him that was even worse. "You… you know, don't you Rose? I wouldn't… I would never just, just fly off without you."

"Doctor," and now her tone was definitely scolding. "Of course I know. You showed me how you felt, remember?"

Of course he did. It was their first argument. Pent up tension after the first few days after Bad Wolf Bay Part II had resulted in quite an explosion of emotion from both of them. He wouldn't really say it was an argument, although they had argued for part of it, and there had been a lot of different issues that had come to light that they had to work through, were still working through, but one thing he had wanted and been able to put to rest immediately was Rose's uncertainty of the Doctor's feelings, considering the full Time Lord had left her without even a good-bye. That had been the first time they had connected telepathically. It was the best way he could think of to show her he loved her, absolutely, unequivocally, and irrevocably.

The Doctor nodded in answer to Rose's question, but he didn't say anything else. Rose sighed. "I'll have a talk with her, yeah?"

"No," he spoke up, then on seeing her raised eyebrow, softened his tone, "no. I think… this is probably something Jackie and I have to work out ourselves." Actually, he thought there was a lot he and Jackie needed to work out themselves. But that was for another day.

Rose still looked concerned, but she agreed. "Okay."

He contemplated her for a moment, before deciding he had one more thing to say. "Rose, if the TARDIS is ever fully grown…"

"You mean _when_ the TARDIS is fully grown," she corrected.

He couldn't help but smile at her faith in him, in them. "When she's grown," he agreed, then became more serious again, "if you decide that you don't want to travel, that you want us to stay on earth with you're family…"

"Stop," she interrupted again, sounding exasperated, but not angry (thank goodness). She walked up to him and took both his hands in hers. "Doctor, mum was always going to be worried about us going out there again. She loves us."

He looked at her dubiously. "She loves _you_ ," he said.

"She loves _you_ , too," she insisted. "She doesn't always _like_ you, but she loves you."

The Doctor wasn't so sure, but didn't object again.

"But I know where our place is," Rose continued, tightening her grip in his, "where we're meant to be. The Doctor in the TARDIS with Rose Tyler, remember? Just as it should be."

He smiled at her quote of the full Time Lord Doctor's words, just before leaving them in this world with their piece of TARDIS coral. Still, he had to ask. "And if we never get her to fly?"

Rose pulled one of her hands from his and brought it up to his cheek, her gaze at him unwavering, "Long as she's with us, and as long as I'm stuck with you," she said, "s'all I need."

Well, at that, he couldn't help but pull her back into his arms again – really, she had been out of them for much to long – and hug her tight, lifting her up off the ground. She giggled, (and oh, did he love that sound) and hugged him back.

"However long we're on earth," he said as he set her down, "and however long we're not, you'll always be stuck with me, Rose Tyler. I'm not going anywhere without you, not unless you want me to."

"Never gonna happen," she told him happily.

He kissed her briefly before catching one of her hands and beaming at her. "You know, Rose, you were wrong about one thing."

"Oh?" Her eyebrow was raised in challenge, but she was smiling back at him. She always did.

"I've still got two hearts. This one," he brought their joined hands up to his chest, "and you."


End file.
